1. Field of the Invention
The present invention relates to a field apparatus control system for controlling the field apparatus of various plants, such as a power plant, and a storage medium which a computer can read.
2. Description of the Prior Art
As shown in FIG. 10, a field apparatus control system 50 for controlling a field apparatus has a field apparatus control system main body 51 for controlling a plurality of field apparatuses 53, which are slaves for controlling a plant apparatus, connected to a field bus 52.
The field apparatus control system main body 51 comprises a field bus communication control unit (master) 54 for performing information (data) communication processing between a plurality of field apparatuses 53 and the local field apparatus control system main body 51 via the field bus 52, a main control unit 55 having a CPU for controlling the field apparatuses 53 and a memory for storing a data program, and a driver 54 which is incorporated into the main control unit 55 (memory thereof) for controlling data input/output processing between the field bus communication control unit 54 and the main control unit 55.
This memory includes a storage medium, such as a floppy disk, magneto-optical disk CD-R (Compact Disk-Recordable), CD-R/W (Compact Disk Rewritable), DVD (Digital Versatile Disk), and IC memory, and the main control unit 55 has a drive unit, according to the type of the storage medium, as a memory, so that a data program can be read/written from/to the memory.
One field bus communication control unit 54, which is a master, is set for a plurality of slaves (field apparatuses) 53. The data transmission path of the field bus 52 is structured as a single transmission path, as shown in FIG. 10.
In other words, the main control unit 55 performs, by operations based on the driver 56, processing for inputting the apparatus status information (status information) transmitted from the field apparatuses 53 side to the local main control unit 55 via the field bus communication control unit 54, and processing for outputting the information, such as a control instruction, to the field apparatuses 53 via the field bus communication control unit 54.
However, according to a conventional field apparatus control system, if the field bus communication control unit 54 or a field bus (transmission path) 52 fails, data input/output operations between the field apparatus 53 and the main control unit 55 stop, thereby reducing the reliability of the field control unit.